The goal of this study is to investigate the utility of labetalol for cocaine dependence in humans. A total of 12 subjects (6 men and 6 women) will be enrolled in this double-blind, placebo controlled inpatient study. Subjects will be assigned to either low (0.25 mg/kg) or high dose of labetalol (0.5 mg/kg), or saline pretreatment group for the first experimental session and then will be crossed over to the alternative pretreatments for the second and third experimental sessions (crossover design). A single dose of cocaine (32 mg/70 kg) will be administered 15 min after labetalol or saline pretreatment. We propose that several physiological, behavioral and subjective effects of cocaine will be significantly blocked by labetalol pretreatment.